Subject:
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Re: Rechargeable Batteries - with correct link :)
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Newsgroups:
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lugnet.off-topic.geek
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Date:
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Thu, 19 Jun 2003 09:47:45 GMT
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Viewed:
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354 times
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Subject: Re: Rechargeable Batteries
From: "Lars Gjerløw Jørgensen" <lgjPURGE@jyde.dk>
Newsgroups: lugnet.off-topic.geek
TJ Avery's utterance expressed in news:HGFAzq.1xBp@lugnet.com:
> I'm trying to estimate the amount of power needed for a project, one
> that will be powered by rechargeables.
What project?
> Rechargeable batteries typically have two ratings: Volts and
> Current-Time. For example, a AA will be 1.2V and 1000 mA-h.
They are available in 2000 mAh too.
> Let's say I'll need to power motors that will require 9V and will draw
> 3 to 4 amps of current. I'll need 8 batteries to get the 9V, but what
> about the current requirements? What exactly does the "mA-h" rating
> mean?
Many 9 volt motors can easily run on the 7.2 volts from 6 x 1.2V. I
akways use rechargeables for my rcx's - although the torque is a
little smaller. If you use 8 you will probably have the juice you need
:) The mAh rating is a way to tell the energy in the batteries.
e.g. 1.2 V 2000 mAh Ni-MH battery.
1.2 V x 2A x 1h = 2.4Watts in one hour = 8640 Joules of energy. But that is
only theoretically speaking. If it was absolute, the battery manufacturers
could just show the energy capacity for a battery. They don't - and they
can't. Because batteries work chemically and not as simple as the above
calculation :(
> I've found some nice NiMH C-cells that have a 5000 mA-h rating. Does
> that mean that they'll provide 5 amps for about 1 hour?
technically yes... but probably only statistically - when used in one
special way. The energy provided by batteries often depend a lot of the
current drawn from the battery. The trouble about rechargeables is that
they provide the energy somewhat diffferent than alkalines. Alkalines
provide high voltage for a period and then drops suddenly and stops
working. Most rechargeables as well as (brownstone) regular batteries drops
voltage over a longer period.
See http://www.duracell.com/oem/Comparisons/
- and http://www.howstuffworks.com - search battery.
Best regards - leg godt!
--
| lars gjerløw jørgensen | lgj[at]jyde[dot]dk |
| N55 43.184 E12 32.405 | www.lgj.dk | oz2lgj |
Mark Hamill:"I have a sneaking suspicion that if there were
a way to make movies without actors, George (Lucas) would do it."
--
| lars gjerløw jørgensen | lgj[at]jyde[dot]dk |
| N55 43.184 E12 32.405 | www.lgj.dk | oz2lgj |
Mark Hamill:"I have a sneaking suspicion that if there were
a way to make movies without actors, George (Lucas) would do it."
|
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Message has 1 Reply:
 | | Re: Rechargeable Batteries - with correct link :)
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| ----- Original Message ----- From: "Lars Gjerløw Jørgensen" <lgjPURGE@jyde.dk> To: <lugnet.off-topic.ge...ugnet.com> Sent: Thursday, June 19, 2003 10:47 AM Subject: Re: Rechargeable Batteries - with correct link :) <snip> </snip> (...) drops (...) (...) (21 years ago, 21-Jun-03, to lugnet.off-topic.geek)
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Message is in Reply To:
| | Rechargeable Batteries
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| I'm trying to estimate the amount of power needed for a project, one that will be powered by rechargeables. Rechargeable batteries typically have two ratings: Volts and Current-Time. For example, a AA will be 1.2V and 1000 mA-h. Let's say I'll need (...) (21 years ago, 13-Jun-03, to lugnet.off-topic.geek)
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